1. Field of the Invention
This invention relates generally to a cassette tape player with a built-in radio receiver and, more specifically, to a cassette tape player with a built-in radio receiver in which the radio receiver is formed on a circuit board arranged within the cover of the tape player along with the radio antenna to receive broadcast information without interference.
2. Description of the Prior Art
There are now known miniaturized, portable tape cassette players that reproduce stereophonic music signals from a prerecorded cassette tape for listening by use of similarly miniaturized headphones. Such tape players are typically of a size that can be easily accommodated in one hand, and many are so small as to be inserted into a shirt pocket.
Following the introduction of these small cassette tape players there have been units produced that incorporate a built-in radio receiver, so that not only can the tape programs be reproduced through the headphones but also radio broadcasts, both AM and FM, can be received and listened to through the same headphone set. In such tape players incorporating a built-in radio certain components are commonly utilized, for example, the electrical source, that is, the batteries, are used in common, as are the audio amplifier and the headphone amplifier. These units are used in common by both the radio receiver part and the tape recorder part in order to maintain the overall size of the unit as small as possible. In employing such commonality of parts and the incorporation of the two functionally different musical sound sources, it is necessary that the radio receiver portion be incorporated into the tape player, since the constituent elements of the tape player are fixed in their physical relationships. This then requires that the radio receiver be separated into parts or segments and that these segments be incorporated into the various, several empty spaces available in the interior of the tape player. Because such empty spaces are at different locations around the interior of the tape player, it becomes necessary for the radio receiver to be divided into several sections or segments with the location of such segments corresponding to the vacent spaces within the interior of the tape player. It is such arrangement of the radio receiver into these various parts that results in the integrated radio receiver having a complicated electrical wiring requirement relative to a conventional, unitary radio receiver. Perhaps most importantly, when the tuner unit of the radio receiver is divided into several sections, as required for the reasons set forth above, the lead length must necessarily be increased, which results in an increase in stray capacitance between such leads, thereby increasing the possibility of unwanted oscillations in the radio receiver circuitry.
Additionally, the tape drive elements in the tape cassette player, such as the capstan, the motor casing, and the chassis located within the main body of the tape player must necessarily be made of a metallic material in order to provide the necessary mechanical strength. Quite frequently, the bar or rod antenna of the AM receiver, which may include a ferrite rod, must necessarily be located in proximity to such metallic components, with the result that the radio waves being received are obstructed and interfered with by these metallic parts on their way to the rod antenna. This antenna location situation severely reduces the sensitivity of the radio receiver. In regard to receiving FM signals, the electrical conductors connecting the earphone headset to the tape cassette player or radio receiver typically provide the desirable thirty-inch antenna length optimum for use in receiving FM radio signals.